Handling of granular material



Dec. 14, 1965 H. STERN HANDLING OF GRANULAR MATERIAL I 5 Sheets-Sheet 1III" Filed June 16, 1964 Dec. 14, 1965 H. STERN 3,223,288

HANDLING OF GRANULAR MATERIAL Filed June 16, 1964 s Sheets-Sheet 2 Dec.14, 1965' H. STERN HANDLING OF GRANULAR MATERIAL 3 Sheets-Sheet 5 FiledJune 16, 1964 United States Patent 3,223,288 HANDLING OF GRANULARMATERIAL Hans Stern, 17 Morris Crescent, Selection Park, Springs,Transvaal, Republic of South Africa Filed June 16, 1964, Ser. No.375,579 Claims priority, application Republic of South Africa, June 26,1963, 63/2,864 4 Claims. (Cl. 222-194) This invention relates to thehandling of granular material.

For the purposes of this specification, the term granular material isintended to include any material comprising discrete particles. Theparticles may be in powdered or granulated form or may be amorphous incharacter or may be in the nature of flakes.

It is well known to convey granulated material in finely powdered formby fluidizing the material with gaseous medium under pressure to permitflow of the material along a conduit in similar manner to a fluid. Inorder to feed the granular material into a conduit carrying fluidizinggaseous medium under pressure, it is known to provide apparatusincluding a cylindrical casing; a rotor with a plurality of radiallyextending vanes rotatable within the casing; a material inlet into thecasing through its peripheral wall; and a material outlet from thecasing through its peripheral wall into the conduit, the outlet beingcircumferentially spaced from the inlet. Each pair of adjacent vanesforms a pocket which during rotation of the rotor carries materialentering the casing, from the inlet to the outlet where it enters theconduit. The clearances between the edges of the rotor vanes and thecasing are as small as possible so as to minimize any tendency forgaseous medium to pass between the outlet and the inlet. The feedingapparatus therefore also acts as a fluid seal.

Apparatus similar to that described above may be used to transfergranular material from a low pressure zone to a high pressure zone.Alternatively, the apparatus may be used to convey granular materialfrom a high pressure zone to a low pressure zone.

Conventional apparatus as described above suffers from the disadvantagethat no matter how small the clearances between the rotor vanes and thecasing, solid particles are inclined to enter between the vanes and thecasing, thus causing wear. Such wear occurs even where the granularmaterial is not considered to be abrasive.

It is an object of the present invention to minimize the abovedisadvantage.

According to the invention apparatus for handling granular materialincludes a first surface; at least one vane disposed transversely to thefirst surface and presenting a second surface disposed in opposed,spaced relationship to the first surface, the vane and the first surfacebeing relatively movable; and a fluid passage in the vane adapted todischarge fluid under pressure into the space between the two surfaces.

A gas or a liquid may be discharged into the space between the twosurfaces.

Fluid discharged into the space between the two surfaces acts to blowaway small particles of material from between the two surfaces. Thisreduces wear. This also permits the clearance between the two surfacesto be smaller than has been possible hitherto, without fear of the vaneseizing on the first surface. Where different pressures exist onopposite sides of the vane, the smaller clearance that can be achievedminimizes leakage of fluid through the clearance from one side of thevane to the other.

The first surface may be plane or curved.

The vane may be disposed in any suitable angular relationshiptransversely to the first surface. It may be disposed not onlysubstantially at right angles to the first surface, but may also bedisposed at a suitable acute angle to the first surface.

Preferably, the vane is movable along the first surface.

During movement along the first surface, the vane can displace granularmaterial from one zone to another.

The vane may be constituted by a pair of juxtaposed elements which arespaced apart to provide a fluid passage between them through which fluidcan be discharged into the space between the two surfaces.

Rotary apparatus according to the invention may include a casing; amaterial inlet into the casing; a material outlet from the casing spacedfrom the inlet; and a rotor rotatably located within the casing, therotor including a hollow drum arranged for fluid under pressure to beintroduced thereinto, and a plurality of circumferentially spaced vanesextending radially from the drum towards the casing with each pair ofadjacent vanes forming a pocket for transferring material from the inletto the outlet, each vane presenting a surface disposed in opposed,spaced relationship to an inner surface of the casing and each vanefurther including a fluid passage which communicates with the interiorof the drum and has an outlet at the vane surface.

The rotor may be constituted by a plurality of substantially similar,juxtaposed and axially extending segments of substantiallychannel-shaped cross-section, the segments being mounted incircumferentially spaced relationship about the rotational axis of therotor so that the bases of the segments form the drum, and so thatopposed flanges of each pair of adjacent segments are spaced apart andform a vane with a fluid passage between the opposed flanges.

Preferably, a fluid pervious packing is located in the fluid passage inthe or each vane.

A preferred embodiment of the invention will now be described by way ofexample with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of granular material handling apparatusincluding a rotary feeder according to the invention.

FIGURE 2 is a section on line IIII in FIGURE 1.

FIGURE 3 is an enlarged sectional view of the rotor and outer casing ofthe feeder of FIGURES 1 and 2.

FIGURE 4 is an enlarged, exploded perspective view of portion of theelements constituting the rotor of the feeder of FIGURES l and 2.

FIGURE 5 is a section to an enlarged scale on the line VV in FIGURE 2.

Feeder 1 includes casing 2 having material inlet 3 in communication withhopper 4 and material outlet 5 in communication with conduit 6. Rotor 7is rotatably mounted within casing 2 on shaft 8 which is coupled todriving motor 9.

Rotor 7 is constituted by a plurality of similar, juxtaposed and axiallyextending segments 10 of channelshaped cross-section. As will be clearfrom FIGURES 2, 3 and 4, segments 10 are arranged in circumferentiallyspaced relationship about shaft 8 so that the spaced, opposed flanges11a, 11b of each pair of adjacent segments 10 form a radial vane 11providing a fluid passage 12 and so that the bases 13 of segments 10form a hollow drum 14.

Segments 16 are secured at opposite ends, as by welding, between endrings 15a, 15b which act as end closures for segments 10 so that betweeneach pair of adjacent vanes 11 a pocket 24 is formed for transferringmaterial from inlet 3 to outlet 5. Segments l0 and end rings 15a, 15bare mounted on shaft 8 for rotational movement therewith, by means ofspokes 16.

The longitudinal tips of vanes 11 present radially outwardl facingsurfaces 17 which are opposed to, and are aazacss located in closelyspaced relationship to the inner peripheral surface 18 of casing 2. Thefluid passage 12 in each vane 11 communicates with the interior of drum14 and has a longitudinally extending, radially facing outlet betweenthe'surfaces 17 of the vanes 11.

A fluid pervious packing 19 in the nature of a sheet of felt which isfolded double and contains a retaining pin 20 in fold 19a is insertedinto each fluid passage 12 in a vane 11 from the interior of drum 14 sothat the folds 19a containing retaining pins 20 seat against the innerperiphery of drum 14. Folds 19a round pins 20 are larger than the widthof passages 12 and prevent packings 19 being displaced outwardly frompassages 12.

Endplate 2b of casing 2 is provided with fluid inlet 21 connected tosupply pipe 22. Fluid inlet 21 is in communication with the interior ofdrum 14 through the aperture ofend ring 15b.

In use, any suitable fluid is introduced under pressure into theinterior of drum 14 through supply pipe 22. The fluid under pressurepercolates'through the pervious packings 19 and discharges through theoutlets of fluid passages 12 as indicated by arrows A.

Granular material 23 which is required to be conveyed, is fed intohopper 4. During rotation of rotor 7, the material 23 gravitates intosuccessive pockets 24 formed by adjacent vanes 11 which pass materialinlet 3 in casing 2. In the result, successive pockets 24 carry batchesof material 23 from material inlet 3 to material outlet where thematerial drops out of pockets 24 into conduit 6. Any suitable fluidunder pressure is introduced into conduit 6 as indicated by arrows B,thereby to fluidize material 23 in known manner to permit flow ofmaterial 23 along conduit 6 in similar manner to a fluid.

Feeder 1 acts as a seal between conduit 6 and feed hopper 4 to preventconveying fluid under pressure from blowing out through hopper 4 fromconduit 6.

As described above, fluid which is introduced under pressure into drum14 discharges radially outwardly through fluid passages 12 in vanes 11as indicated by arrows A. The fluid outlets in vane tips facing innerperiphery 18 of easing 2 discharge fluid under pressure into the spaces26 between periphery 18 and vane tip surfaces 17 opposed to periphery18. The spaces 26 between the vane tips and the inner periphery 18 ofcasing 2 are small so that the escaping fluid produces suflicientpressure and velocity to blow away small particles of material frombetween the vane tips and inner periphery 18 of casing 2. This reduceswear. This also permits the clearances between the vane tips and innerperiphery 18 of easing 2 to be smaller than has been possible hitherto,without fear of vanes 11 seizing on casing 2. The smaller clearancesthat can be achieved minimizes leakage of conveying flu-id through theclearances from conduit 6 to hopper 4 so that an improved fluid sea-1can be obtained.

Fluid discharged from the vane tips facing material inlet 3 in casing 2tends to fluidize material 23 entering from hopper 4. This minimizeschoking of inlet 3 and also assists the fluidization occurring inconduit 6.

Annular seals 25a, 25b are provided to prevent escape of fluid from theinterior of drum 14 between the end plates 2a, 2b of easing 2 and theend rings a, 15b of rotor 7.

With the arrangement illustrated in the accompanying drawings, end rings15a, 15b are continuous and close off the transverse ends of fluidpassages 12 in vanes 11 which face end plates 2a, 2b of casing 2. Inother words, it is only the radially facing, longitudinal surfaces 17 ofvanes 11 which are opposed to the inner periphery 18 of easing 2 inaccordance with the invention. The inner periphery 18 of easing 2constitutes a first surface of the invention which is curved.

It is also possible to arrange vanes 11 to present longitudinallyfacing, transverse end surfaces opposed to end plates2a, 2b of casing 2,the transverse ends of fluid passages 12 being open to discharge fluidinto the spaces between the ends of vanes 11 and end plates 2a, 2b. Endplates 2a, 2b will then each constitute a first surface of the inventionwhich is plane.

Instead of providing vanes 11 with fluid passages 12 extendingcontinuously along the whole length and depth of the vanes, any othersuitable fluid passage arrangement may be used. For example, vanes withone or more grooves or recesses in their tips constituting fluid outletsextending along the whole or part of the length of the vanes may beprovided, one or more radial passages in the vanes placing the outletgrooves or recesses in communication with the interior of drum 14. Itwill be appreciated that the drum and radial vanes of the rotor may beconstructed in any other suitable manner.

Many other variations in detail are possible without departing from thescope of the appended claims.

A feeder similar to that illustrated in the accompanying drawings may beused for transferring granular material between any two zones atdiflerent pressures.

I claim:

1. Apparatus for handling granular material comprising a casing; amaterial inlet into the casing; a material outlet from the casing spacedfrom the inlet; a rotor rotatably located within the casing, the rotorcomprising a hollow reservoir for fluid under pressure, a fluid inletinto the reservoir, a plurality of circumferentially spaced vanesextending radially from the reservoir towards said casing with each pairof adjacent vanes forming a pocket for transferring material from theinlet to the outlet, each vane presenting a tip surface disposed inopposed spaced relationship to an inner surface of the casing, a fluidpassage in each vane in permanent communication with the interior of thereservoir and with an outlet located substantially centrally in the tipsurface in a transverse direction and extending substantially the wholelength of the tip surface, and a fluid pervious packing in each fluidpassage at and along the outlet.

2. Apparatus for handling granular material comprising a casing; amaterial inlet into the casing; a material outlet from the casing spacedfrom the inlet; a rotor rotatably located within the casing, the rotorcomprising a hollow reservoir for fluid under pressure, a fluid inletinto the reservoir, a plurality of circumferentially spaced vanesextending radially from the reservoir towards the casing with each pairof adjacent vanes forming a pocket for transferring material from theinlet to the outlet, each vane presenting a tip surface disposed inopposed spaced relationship to an inner surface of the casing, a fluidpassage in each vane in permanent communication with the interior of thereservoir and with an outlet located substantially centrally in the tipsurface in a transverse direction and extending substantially the wholelength of the tip surface, and a fluid pervious packing in each fluidpassage at and along the outlet, each packing comprising a sheet offluid pervious material which is folded double and contains an elongatedretaining element in the fold, the folded sheet being located in thefluid passage with the fold containing the retaining element locatedwithin the reservoir against the inner periphery thereof.

3. Apparatus for handling granular material comprising a casing; amaterial inlet into the casing; a material' outlet from the casingspaced from the inlet; a rotor rotatably located within the casing, therotor being constituted by a plurality of substantially similar channelmembers mounted in circumferentially spaced, axially extendingjuxtaposition about the rotational axis of the rotor whereby the basesof the channel members form a hollow reservoir for fluid under pressureand opposed flanges of each pair of adjacent channel members are spacedapart and form a vane presenting a tip surface disposed in opposed,spaced relationship to an inner surface of the casing, the space betweeneach pair of adjacent vane forming channel members constituting a fluidpassage in the vane which is in permanent communication with theinterior of the reservoir and has an outlet located substantiallycentrally in the tip surface in a transverse direction and extendingsubstantially the whole length of the tip surface, and a fluid perviouspacking between opposed flanges of each pair of adjacent channel membersin the communicating passage defined by such opposed flanges at andalong the outlet.

4. Apparatus for handling granular material comprising a casing; amaterial inlet into the casing; a material outlet from the casing spacedfrom the inlet; a rotor rotatably located within the casing, the rotorbeing constituted by a plurality of substantially similar channelmembers mounted in circumferentially spaced, axially extendingjuxtaposition about the rotational axis of the rotor whereby the basesof the channel members form a hollow reservoir for fluid under pressureand opposed flanges of each pair of adjacent channel members are spacedapart and form a vane presenting a tip surface disposed in opposed,spaced relationship to an inner surface of the casing, the space betweeneach pair of adjacent vane forming channel members constituting a fluidpassage in the vane which is in permanent communication with theinterior of the reservoir and has an outlet located substantiallycentrally in the tip surface in a transverse direction and extendingsubstantially the whole length of the tip surface, and a fluid perviouspacking between opposed flanges of each pair of adjacent channel membersin the communicating passage defined by such opposed flanges at andalong the outlet, each packing comprising a sheet of fluid perviousmaterial which is folded double and contains an elongated retainingelement in the fold, the folded sheet being located in the fluid passagewith the fold containing the retaining element located Within thereservoir against the inner periphery thereof.

References Cited by the Examiner UNITED STATES PATENTS 1,777,043 9/1930Lanhoffer et a1. 2,540,059 1/1951 Stirn et a1 222-194X 2,921,721 1/1960Brooks 222-194 X 3,151,784 10/1964 Tailor 222-194 X LOUIS J. DEMBO,Primary Examiner.

1. APPARATUS FOR HANDLING GRANULAR MATERIAL COMPRISING A CASING; AMATERIAL INLET INTO THE CASING; A MATERIAL OUTLET FROM THE CASING SPACEDFROM THE INLET; A ROTOR ROTATABLY LOCATED WITHIN THE CASING, THE ROTORCOMPRISING A HOLLOW RESERVOIR FOR FLUID UNDER PRESSURE, A FLUID INLETINTO THE RESERVOIR, A PLURALITY OF CIRCUMFERENTIALLY SPACED VANESEXTENDING RADIALLY FROM THE RESERVOIR TOWARDS SAID CASING WITH EACH PAIROF ADJACENT VANES FORMING A POCKET FOR TRANSFERRING MATERIAL FROM THEINLET TO THE OUTLET, EACH VANES PRESENTING A TIP SURFACE DISPOSED INOPPOSED SPACED RELATIONSHIP TO AN INNER SURFACE OF THE CASING, A FLUIDPASSAGE IN EACH VANE IN PERMANENT COMMUNICATION WITH THE INTERIOR OF THERESERVOIR AND WITH AN OUTLET LOCATED SUB-